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Ted Coakley
fcp 7 audio/video drift/sync
on Oct 26, 2018 at 2:23:23 am

I have a clip (.MOV, ProRes 422 HQ, 720x480, 48kHz, 29.97, 16-bit Integer (Big Endian), Stereo) that plays just fine in Finder and in QuickTime Player (versions 7.6.6 and 10.3), but in FCP 7.0.3, the audio and video drift out of sync, more and more as the clip goes on.
By the end of the hour-long clip, the video lags about a second behind the audio.

I saw some threads from 2010 where someone had the exact same problem with his 23.98 footage (which should have been transcoded at 23.976), but my footage I'm dealing with is 29.97.

Anyone here know the solution to this?

Thanks!


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Dave LaRonde
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 2:50:15 am

The farther one gets away from the Apple OS of eight years ago, the weirder FCP gets.
What's your OS?

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 3:34:10 am

Hi Dave, thanks for your reply.

I should've mentioned:
* I'm running OS 10.9.5 (on a 15" Late-2011 MacBook Pro)
* The audio/video drifts out of sync just from playing in the FCP Viewer, before even getting to the Sequence/Timeline, so it is apparently NOT a Sequence Settings issue.
* The clip opens and plays just fine in Premiere Pro 5.5.

Ted


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David Roth Weiss
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 3:56:51 am

Open a new sequence, drag that clip onto the timeline, when the dialog box appears make sure to let FCP match the sequence settings to the clip, and now hit play. Does your audio still drift?

David Roth Weiss
Director/Editor/Colorist & Workflow Consultant
David Weiss Productions
Los Angeles


David is a Creative COW contributing editor and a forum host of the Apple Final Cut Pro forum.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 4:16:09 am

Hi David, thanks for your reply.

Yes, the audio still drifts after Clip placed in Timeline and FCP matches Sequence Settings to Clip.
It still drifts in Timeline/Canvas playback, same amount as drift in Viewer.

Ted


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David Roth Weiss
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 4:38:51 am

You might try transcoding that clip in Adobe Media Encoder. But, is that clip possibly from a phone, transcoded to Pro Res?

David Roth Weiss
Director/Editor/Colorist & Workflow Consultant
David Weiss Productions
Los Angeles


David is a Creative COW contributing editor and a forum host of the Apple Final Cut Pro forum.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 4:43:51 am

That clip was already transferred/transcoded from a miniDV tape to ProRes, so I'd rather not re-transcode it and suffer another generation loss.
I'd rather just have FCP play it back correctly, like QT, Finder and Premiere Pro do.


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Dave LaRonde
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 6:22:49 pm

Apparently you didn't use the Easy Setup in FCP to bring it in via Firewire in Log and Transfer. It would have come in as DV... which is okay, because it's losing no quality when you do it.

There's the possibility that the audio on this Mini DV tape had 32kHz audio and not 48 kHz audio. It's been known to cause problems.

It's tough to say what causing it, but I have to think it happened when you transcoded the DV video... however you did it.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 6:55:35 pm

I didn't do the transfer, a transfer house did it, and I think they said they DID ingest it as a DV file - and maybe they used Easy Setup (I don't know).

Yes, the original footage was 32kHz (from Sony VX1000), but once transcoded to 48kHz, it plays totally fine in QT, Premiere, Finder, so why wouldn't it play fine in FCP 7? All FCP 7 sees is a file with 48kHz audio.

Are you saying that video with 32kHz audio can't be transcoded to video with 48kHz audio, and still play in FCP7 - or is there a specific way or settings necessary in the transcode process?
If the latter, what is that specific way or settings?


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Dave LaRonde
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 8:11:00 pm

Is it possible for YOU to ingest the tape in FCP using Firewire? You don't have to do the whole thing, maybe just 10 minutes. That should give you a good indication if audio & video are separating.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 10:41:17 pm

I would ingest into FCP 7 via firewire, if my Sony DSR-11 or Sony VX-1000 were working right, but they're not at the moment.
If I did, what would that gain me?
I already know for sure that the video file with audio/video drift in FCP7 plays fine (with no audio/video drift) in Finder, QT and Premiere, so the file appears fine.
What good would it do for me to transcode another copy of the video?


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Dave LaRonde
Re: fcp 7 audio/video drift/sync
on Oct 26, 2018 at 11:13:52 pm

You wouldn't transcode -- you'd bring it in as DV. Log & Transfer doesn't alter one pixel of the video. It's pristine.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 27, 2018 at 5:14:38 am

Do you mean Log & Capture (instead of Log & Transfer), to bring it in from miniDV tape as pristine unaltered DV?
(I've always used Log & Capture to ingest from tape, but didn't know that's possible with Log & Transfer.)

In either case, what good would the pristine unaltered DV file do me? What are you suggesting I do with that file?


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 27, 2018 at 5:55:09 am
Last Edited By Nick Meyers on Oct 27, 2018 at 5:57:30 am

hi Ted.
its strange alright, i don't really know if there's a simple answer.
-can you get the DV capture from the post house that did it?

other approaches:
1.
re-sync the audio in a FCP timeline, and export
2 ways to do this: every 150 seconds, adda frame, or rather duplicate a frame of audio,
(blade the audio and slip the right hand side 1 fr)
(NB the 150 seconds is according my calculations, which could easily be wrong, I'm a bit tired, maybe you should double check them!)

find you end sync point, and trim the audio to there
double click into the viewer,
mark in/outs around your picture in the timeline
and do a fit to fil edit back into the timeline (drag to GREEN window in canvas, or Shift+F11)
this will stretch it out to fit the image.

exporting from FCP will NOT add generational loss to your video,
if you export a QuickTIme move, using the default "Same Settings"

2.
extract or export the audio from the QT file
maybe bringing that int FCP it will behave???

one more thing to look into:
do your sequence presets match your clip?
there is a known fault in FCP where imported AUDIO ONLY will take on the frame rate of the selected sequence preset,
and if that does match your video frame-rate, then the audio will drift against the video when synced.

its hard to believe that this could cause a file containing both the video and audio to drift within itself,
but who knows??


good luck with it,
nick


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 27, 2018 at 7:07:39 am

Thanks for your reply, Nick.

As for selected sequence preset being set correctly (I'm thinking you mean Sequence Settings), are you saying to have those Sequence Settings fps match the Clip's fps?

When I open the Clip in MPEG Streamclip, I can see that the video fps is 29.975.

Here's what I tried:
... I go to FCP7 "Sequence Settings" > "QuickTime Video Settings" area > "Advanced" button, which opens the "Compression Settings" dialogue box > where I go to the "Motion" section > "Frames per second" dropdown menu (you following?)
... In that dropdown menu, I can choose from many fps options, including 29.97 and "custom", but no 29.975.
... I choose "custom", which brings up a box next to it. I type "29.975" in that box, hit the "OK" button to close the "Compression Settings" dialogue box, and then "OK" button to close the "Sequence Settings" dialogue box.
... Then, I go back to the Compression Settings area, and it no longer says Custom or 29.975, but rather just 29.97.

... Whaddya think? Whaddya suggest?
Thanks,
Ted


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Oct 27, 2018 at 11:45:28 pm
Last Edited By Michael Gissing on Oct 27, 2018 at 11:46:16 pm

I'm going to hazard a guess that the metadata in the file incorrectly has the frame rate set to 29.975 no 29.97. It makes me wonder if the DV was converted to ProRes in something like After Effects which can set frame rates with incorrect speed.

Final Cut Pro unlike most other apps tries really hard to apply incorrect metadata like that to what it can. In this case to the audio as a frame is a frame. This may be causing your audio drift.

If you have Cinema Tools, open the file in there and change the frame rate metadata to 29.97. (You should do this to a copy of the file just in case as this is not an undoable operation).

Try this file in a matching sequence and see what happens.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 12:14:43 am

Hi Michael, thanks for your reply.

Yes, I believe you're correct. As I mentioned in my previous reply in this thread, MPEG Streamclip shows the clip to be at 29.975.
That clip came from a VX1000 miniDV tape ingested (Log/Capture) by FCP 7, and then converted to ProRes from an FCP 7 export.

I don't have Cinema Tools on my computer, but I'm looking online for where to download it right now.....
SO far, I've found http://www.fcp.co/final-cut-pro/articles/1859-macos-sierra-cinema-tools-is-..., with links to https://support.apple.com/kb/DL949?locale=en_US, which says latest version of Cinema Tools is 4.5.1

I also just found my FCP7 install files on my computer, which I think will allow me to install Cinema Tools - which I must not have known of a reason to install, back when I installed FCP7 - or maybe it was because the Installer says it'll consume 780MB of my hard drive (as I see now that I launched the Installer).

I wonder if there's another lighter-weight program/utility I could download, or already have, to change the clip's metadata.
Searching online now.....

Stay tuned.....


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 12:41:49 am
Last Edited By Nick Meyers on Oct 28, 2018 at 12:43:06 am

nothing lighter than CinemaTools
its a small app, very easy to use,
and you have it.
what's that they say about a bird in the hand?

good idea from michael, btw

n


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 12:47:26 am

Yeah, I hear ya! About to install it.
Once installed, there will be some relatively simple to find and simple to use function to just change the clip's frame rate tag in it's MOV file?


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 12:50:57 am

Well, shoot. I just installed Cinema Tools, and when I go to launch it, all I get is this error message:

"Cinema Tools quit unexpectedly while using the Cinema Tools plug-in.
Click Reopen to open the application again. Click Report to see more detailed information and send a report to Apple."

My options are "Ignore", "Report" and "Reopen" - none of which allow me to launch Cinema Tools, despite repeated attempts :-/


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 1:04:14 am

Alright, I followed my link from my earlier post, updated Cinema Tools ("CT") to 4.5.1 (latest available, I think), and now it works in my OS 10.9.5 ☺

I launched CT, opened the problem .MOV file in CT, clicked the Analysis button, where a) it shows 29.97fps (not 29.975, despite 29.975 showing up in Premiere and MPEG Streamclip), and b) doesn't allow me to change the the frame rate. Furthermore, I don't see anywhere to change any of the metadata of the .MOV file/clip, in CT.


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 1:06:27 am

open the clip in CT
at lower left click on he "Conform" button
choose your free rate.

good luck
nick


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 1:08:05 am

if 29.97 isn't available,
try confomring to any other frame rate, then back to 29.97

n


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 1:15:33 am

Conform button is in lower right (FWIW).

29.97 is available, but 29.975 is not. Other frame rates are nothing close to 29.97.

CT already says clip is at 29.97 (despite other programs saying it's at 29.975), so, what would Conforming do?

Will Conforming cause re-encoding or transcoding or making a new file - or just change the metadata?


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 1:42:58 am
Last Edited By Michael Gissing on Oct 28, 2018 at 1:43:42 am

Cinema tools will display 29.97 because 29.975 is not a real rate. Choose conform to 29.97 and it will just correct the metadata flag to 29.97 so FCP can play it correctly without sync drift.

Conform only changes the metadata. It doesn't re-render.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 7:55:42 am

Ta-dow, boo-yah, bam, lordy-lord, heavens to betsy, oh my..........

It worked! The conforming to 29.97 in Cinema Tools ("CT") seems to have solved the audio/video drift problem in FCP7 > Viewer ☺

Even with all my tweaked settings I had set up in FCP7, in trying to solve this (32kHz, 29.975, every 3rd blue moon, standing on one foot, etc), once I imported the CT-conformed 29.97fps clip, it played back fine in FCP7 Viewer (and Timeline/Sequence)

Next, I re-set my FCP7 settings (Easy Setup; Audio/Video Settings >Sequence Presets & Capture Presets; Sequence > Settings) all back to the simple out-of-the-box DV NTSC 48kHz, and my newly 29.97 CT-conformed clip still played back fine in FCP7.

Furthermore, looking at this newly 29.97 CT-conformed clip in Premiere Pro 5.5 ("PP") and in MPEG Streamclip (both places that showed 29.975 before I conformed it), it now reads as 29.97 in both MPEG Streamclip, and in ONE part of PP (Clip>Modify>Interpret Footage>Frame Rate>Use Frame Rate from File), but STILL reads 29.975 in another part of PP (Window>Metadata>File>Dynamic Media>Video Frame Rate).

Seeing that PP's Metadata reader is still showing 29.975 leaves me wondering which metadata was actually changed in the file, especially because MPEG Streamclip now shows it to be 29.97, and (most importantly) it now WORKS in FCP7.
At this point, this is maybe over my head, and I guess not relevant to me (since it just works in FCP7 now!), but perhaps useful info to someone else troubleshooting a related issue.

**OH SHIT ALERT**
Right when I was about to post this message, I checked the PLAYBACK of the 29.97 CT-Conformed clip in MPEG Streamclip (works fine), and in PP (does NOT play fine).
In PP, I had already done an edit with the pre-CT-conformed clip (29.975), which PP handled just fine (https://www.youtube.com/watch?v=TjpcvK0pK9c, if you're interested).
BUT, once I opened PP back up to check its Metadata reader (as I mentioned earlier), both the Clip and Timeline/Sequence audio playback are faulty in ways all over the map (sometimes mute, sometimes fine, sometimes high distortion, sometimes playing audio from other faraway parts of the clip)
I guess that since my PP Clip Import and Timeline/Sequence were based on a clip originally with 29.975 metadata, and that clip that PP points to/references is now the newly 29.97 CT-conformed clip, PP's audio playback is now thrown out of whack.
I do still have my original pre-(or non-) CT-conformed clip that I can have this PP edit refer to for proper playback (unless someone can now tell me how to get my PP edit to now play nicely with the 29.97 CT-conformed clip), and then use the 29.97 CT-conformed clip if I want to use it on my FCP7.

AND NOW, back to this message about 30 minutes after previous comments in this message, the 29.97 CT-conformed clip is playing back FINE in PP. (except for a handful of edit points now off by 10-15 frames here and there, which I just cleaned up, so it seemingly now works fine with the 29.97 CT-conformed clip)
Go figure!

Hoo-doggie - that's a lot!

Finally, FWIW, Michael, I didn't understand when you said that 29.975 is not a real rate, since I've read all over the interwebs that true NTSC is not actually 29.97, but, rather 29.975 or 29.976 (I see both mentioned a lot). You saying NTSC is not either of those, but just 29.97?
Just curious.

Big big thanks Nick, Michael, Dave and David - for your help with this!
And to all, a good night!


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 8:52:49 am

Not so fast on the "good night" at the end of my last post :-/

Now, that newly 29.97 CT-conformed .MOV file doesn't play in Finder (via Quick Look) - even though it plays fine in Premiere, QT, FCP7, MPEG Streamclip and Cinema Tools.

I've tried restarting computer, and working in another Finder window - no luck.
Other .MOV files play fine through Quick Look/Finder. Just the one CT-conformed .MOV file is having problems.

I'd like to have that clip play in Quick Look/Finder again, if possible. Anyone know how to get that working again?


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 9:21:57 am

[Ted Coakley] "I'd like to have that clip play in Quick Look/Finder again, if possible. Anyone know how to get that working again?"

try exporting the file from the FCP viewer window, using the default "same settings"
export with the exact same name (basically don't change anything)
cheek the export, then if it plays fine,
replace the original with the export.

exporting from the viewer window will keep the metadata of Reel# and timecode.

nick


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 29, 2018 at 10:51:44 pm

Alright, Nick, here's what I did, thinking this is following your suggestion.

1. Imported file that no longer plays in Finder/QuickLook, but plays well in everything else, into FCP 7 Browser.
2. Opened file in FCP7 Viewer
3. File > Export > Quick Time Movie
4. Settings: Current Settings
Include: Audio and Video
Markers: None
Recompress All Frames: DEselected/UNchecked
Make Movie Self-Contained: Selected/Checked

After about 5 minutes, there is a new .MOV file, same image size and Duration as the original.
The new file is 29.284GB, vs 29.277GB original file (so, pretty close).
And the new file also does not play in the finder/QuickLook, just like the original does not.


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Nick Meyers
Re: fcp 7 audio/video drift/sync
on Oct 28, 2018 at 9:19:03 am

[Ted Coakley] "Finally, FWIW, Michael, I didn't understand when you said that 29.975 is not a real rate, since I've read all over the interwebs that true NTSC is not actually 29.97, but, rather 29.975 or 29.976 (I see both mentioned a lot). You saying NTSC is not either of those, but just 29.97?
Just curious."


29.97 the the "real" frame rate
you are perhaps thinking of 23.976, which is a "real" frame rate that often gets abbreviated to 23.98,
or just 24p


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 29, 2018 at 10:47:19 pm

Thanks, Nick, but I'm not thinking of the "real" frame rate of 23.976 that often gets abbreviated to 23.98 or 24p, as I am as familiar with that as I am with 29.975 or 29.976 being a "real" frame rate that often gets abbreviated to 29.97 or 30p.

Both of those instances are things I've thought to be true, and are also what a guy with local transfer house thinks/says (and he has been transferring NTSC (and many other formats) for 30 years now).

Are you saying that the transfer house and I are wrong in our thinking that NTSC 29.97 or 30p is actually 29.975 or 29.976, and that it actually is just 29.970?


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Oct 29, 2018 at 11:16:14 pm

[Ted Coakley] n"Are you saying that the transfer house and I are wrong in our thinking that NTSC 29.97 or 30p is actually 29.975 or 29.976, and that it actually is just 29.970?"

Basically yes. A shift in frame rate by .1% was decided on all those years ago. Grab a calculator and subtract .1% from 30 and 24. You will see that 29.97 is correct and 23.976 is too. 29.97 is not an abbreviation. The only software that I have heard of that can give an incorrect frame rate like 29.975 is After Effects which is why I was curious if it had been used in the conversion to ProRes. With AE it is also necessary to spec 23.976 not 23.98. All other NLE and VFX software that I know of give options based on actual frame rates. AE allows for user defined frame rates and you have to be precise to the decimal points.

What FCP was trying to do to resolve the issue was varispeed the sound to play back 29.975. However the video rate couldn't be shifted because a frame is a frame. FCP trying to be helpful with changing audio speed has been a constant issue with what was seen as a feature of the program has really behaved like a bug for many of us over the years. Hence people will ask about sample rates, bit depth and the killer problem of having a different default easy setup frame rate. That one really is a bug which will never be fixed. It only affects audio only not a QT file so I knew your issue was incorrect frame rate metadata.

I have no idea why the corrected file is now causing grief in Finder. It is possible that somewhere in the OS the original files metadata was stored and now it doesn't cross reference.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Oct 29, 2018 at 11:44:37 pm

Thanks for the math, Michael.
Yep, I see that .999 x 24 = 23.976, and .999 x 20 =29.970.
So, I get it (with the new knowledge that 0.1% was the intended/desired frame rate shift).

I also get it when you say that AE allows 23.976 setting (and I've mentioned that Premiere does, as well), unlike other NLE/VFXs, but, also as I've mentioned, my initially problematic-for-FCP7-Viewer 29.975 .MOV file, was from a FCP 7 Import to an FCP 7 export.

Hopefully, this clarification may be helpful to anyone that reads this, who might have some insight or explanation.

However, this leaves us (or at least me) wondering a) how the FCP7 export made a 29.975 file, and b) why some people think 29.97 is actually 29.976 or 29.975.


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Oct 29, 2018 at 11:55:59 pm

I'm one of the lucky many that live in a 25fps world (actually most of the TV world is 25fps) but have had to deal with the small but influential 29.97/ 23.976 world and sort out the math to deliver speed corrected pitch correct audio mixes over feature length programs.


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Mark Suszko
Re: fcp 7 audio/video drift/sync
on Nov 1, 2018 at 1:52:01 pm

In all the banter about frame rate, anybody check and match the audio SAMPLE rates?


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Nov 2, 2018 at 12:05:56 am

[Mark Suszko]"In all the banter about frame rate, anybody check and match the audio SAMPLE rates?"

The problem was the incorrect frame rate metadata causing FCP to think the audio was not 48khz @ 29.97, even though it was. Over the years the single biggest cause of audio drift in FCP has not been sample rates but the way FCP applied a frame rate to audio files and then would in the background, varispeed them to correct their frame rate against the sequence frame rate.

In this case the audio sample rate was absolutely correct but the frame rate had been stamped as 29.975. All FCP could do was to drift the audio. I wish FCP had never included in its software this 'feature' of affecting audio speed based on a frame rate metadata stamp. It has been the culprit in most of these sync problems. Sample rate has almost never been the culprit.

Once again in this case the problem was solved when I realised the frame rate metadata was incorrect. When that was fixed using Cinema Tools, the audio drift didn't happen. So no need to check sample rate as it was always correct in this case. I wish a permanent sticky thread outlining FCPs audio behaviour could be applied to this forum.


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Ted Coakley
Re: fcp 7 audio/video drift/sync
on Nov 12, 2018 at 7:23:19 pm

Sorry, Michael, I don't understand this.

You said, "The problem was the incorrect frame rate metadata causing FCP to think the audio was not 48khz @ 29.97, even though it was."
* Do you mean that my FCP7 Viewer could only playback my 29.975 metadata Clip as a 29.970 Clip, and thus the A/V drift?
* And do you mean that my FCP7 Viewer could not see my 48khz clip as 48khz for some reason, and thus the A/V drift?

You also said, "In this case the audio sample rate was absolutely correct but the frame rate had been stamped as 29.975. All FCP could do was to drift the audio."
* Do you mean that my video Clip's ACTUAL fps is 29.970, and its ACTUAL audio is 48khz, but because the Clip's metadata was stamped 29.975, that that causes FCP7 to think, "Oh, since this Clip is 29.975, it must NOT be 48khz, so I'll play it back at a different khz."?
* If so, then at what khz DID my FCP7 choose to playback my 48khz ?
* If not, then what did you mean?

You also, that FCP would "...... varispeed them to correct their frame rate against the sequence frame rate", but keep in mind, this is an issue in FCP7's VIEWER - NOT anything related to FCP7's Sequence, Sequence frame rate, or any other Sequence settings.
* With that in mind, that there's no sequence frame rate against which FCP7 would varispeed, what's your thoughts on the matter?

I'm just trying to get everything totally dialed, understood and setup right, before I dive into a couple hundred hours of archival miniDV transfers (and before I get more of those tapes transferred).
Thanks!


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Bouke Vahl
Re: fcp 7 audio/video drift/sync
on Nov 1, 2018 at 3:29:43 pm

NTSC based framerates are 30 * 1000 / 1001, or 24 * 1000 / 1001
So to be correct, it's 29,97002997002997 and 23,97602397602398

For normal math, to calculate sync stuff for normal content (let's say up to 2 hours), 29.97 is accurate enough, but the rounded 23.98 is not. 23.976 however is way better.
The difference between 23.98 and 23.976 makes for 0.6 seconds over an hour. And 0.6 seconds off, well, that is not accurate enough for us.

hth

Bouke
http://www.videotoolshed.com


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Michael Gissing
Re: fcp 7 audio/video drift/sync
on Nov 1, 2018 at 11:56:10 pm

Yes Bouke. I used to have the 23.976 formula written down to the extra decimals to do an audio file conversion for feature length programs for that very reason. It did matter


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